In the recent years, with the advancement of speeding up of the machines and energy conservation, a toner having excellent low-temperature fixing ability is required. In view of the above, as a resin binder for use in a toner, numerous studies on polyesters having excellent low-temperature fixing ability are made, and among them, a polyester obtained by using a carboxylic acid having an aromatic ring as a raw material monomer capable of improving glass transition temperature while maintaining a low softening point is used. However, a toner using the polyester has a disadvantage that initial rise of triboelectric charging is delayed.
Patent Publication 1 discloses, as an objective of providing a toner having excellent initial rise in triboelectric charging, and moisture-resistant, heat-resistant storage ability, a toner for electrostatic image development containing at least a resin binder, a wax, a colorant, and a charge control agent, the toner for electrostatic image development characterized in that a metal complex of an aromatic hydroxycarboxylic acid is used as the charge control agent, and further that a hydroxylated aromatic hydroxycarboxylic acid compound is contained as a third substance.
Patent Publication 2 discloses a toner obtained by dissolving or dispersing toner materials containing at least a resin binder and a charge control agent in an organic solvent to provide a solution or dispersion, dispersing a solution or dispersion in an aqueous medium, and removing the organic solvent from the dispersion, characterized in that the above-mentioned resin binder at least has an ionically bindable functional group, and that the charge control agent is ionically bonded to the above-mentioned resin binder in the internal of the above-mentioned toner.
Patent Publication 3 discloses, as an objective of providing a toner having excellent low-temperature fixing ability and offset resistance, and being capable of reducing stains in the machines, a polyester for a toner obtained by polycondensing an alcohol component and a carboxylic acid component containing 0.5 to 50% by mol of an alkylsuccinic acid having 10 or more carbon atoms and/or an alkenylsuccinic acid having 10 or more carbon atoms, wherein a polyester for a toner having amounts of 6-methyl-2-heptanone and 5-methyl-2-heptanone detected of 0.5 ppm or less each according to thermal desorption-gas chromatograph-mass spectrometry.
Patent Publication 4 discloses a polyester having excellent hydrolytic resistance usable in the production of a toner including the step of forming particles from raw material components containing a resin binder containing at least a polyester in an aqueous medium or a solution, the polyester being obtainable by polycondensing an alcohol component and a carboxylic acid component containing at least one member selected from alkylsuccinic acids and alkenylsuccinic acids, and a polyester for use in a toner for electrophotography having excellent storage property and fixing ability, containing the above polyester.
In addition, as a resin binder for a toner, a resin binder for a toner containing a crystalline polyester and an amorphous polyester resin is proposed.
In addition, Patent Publication 5 discloses a resin binder for a toner having excellent low-temperature fixing ability, environmental stability, and blocking resistance, the resin binder for a toner containing crystalline polyester and amorphous polyester resins, wherein the crystalline polyester is obtainable by polycondensing an alcohol component containing 70% by mol or more of an aliphatic diol having 2 to 8 carbon atoms, and a carboxylic acid component containing 70% by mol or more of an aromatic dicarboxylic acid compound.
Patent Publication 6 discloses, as a resin binder for a toner having not only excellent low-temperature fixing ability and triboelectric chargeability, but also excellent in dynamic strength, and having excellent durability even in a nonmagnetic monocomponent development method, a resin binder for a toner containing a crystalline polyester for a toner and an amorphous resin, wherein the crystalline polyester for a toner is a polyester obtained by polycondensing an alcohol component containing 70% by mol or more of 1,6-hexanediol and a carboxylic acid component containing 70% by mol or more of an aromatic carboxylic acid compound.